Asymmetric Induction in the Intramolecular 1,3-Diyl Trapping Reaction through the Use of Menthyl and 8-Phenylmenthyl Esters. An Unexpected Result

Article abstract of DOI:10.1021/jo00172a009

Diazenes 4a and 4b bearing (-)-menthyl and (-)-8-phenylmenthyl ester units as chiral auxiliaries were prepared and converted into the linearly fused tricyclopentanoid ring system through utilization of the intramolecular 1,3-diyl trapping reaction.The idealized transition state representations 4a<*> and 4b<*> were shown to be inadequate, for while they were useful in predicting the observed decrease in the cis,anti to cis,syn ring-fusion product ratio as the size of the ester unit increased, they provided an overly simplified view of the expectations associated with asymmetric induction.In no instance was a synthetically useful de value obtained.A brief mechanistic rationale which focuses upon the presumed stepwise nature of the trapping reaction is presented.